Disable media session and media key features

[selurvedu]

What's new in this PR?

Issues

When an audio message or a video is played, Wire is wrongly detected as a media player and takes precedence over other music or video players when a user presses hardware media keys.

The OS may also display Wire as a media player named "Chromium" with play/pause, previous and next controls, of which only the play/pause button is functional. It keeps being show even after the audio message or the video has finished playing.

Causes

Electron enables HardwareMediaKeyHandling and MediaSessionService features by default.

Solutions

Disable those features.

Testing

How to Test

Without this patch

Wire should be visible in the audio controls section in the system tray on Linux (at least on GNOME and KDE) when a user plays an audio message or a video.

The behaviour on Windows should be similar.

It also gets detected as a media player on external devices when using KDE Connect media controls.

Depending on the system configuration, Wire may or may not respond to hardware media keys.

With this patch

None of the above happens.

Notes

I submitted this PR because Wire always ends up showing on my phone with KDE Connect media controls when I play and audio message on my computer, and it remains there until I dismiss a notification or play something in a real media player, or quit Wire. That is because the MedaSession does not get destroyed after the audio message or a video has finished playing, and every play/pause triggers KDE Connect to show Wire as a currently active media player. The media controls section in the system tray does exactly the same thing, but that's not such a big problem since it is not always visible on screen.